Lighting apparatus

Abstract

Of the various technological features disclosed in the present specification, a structure according to the one technological feature is as follows. A lighting apparatus changeable between an illuminating state and a non-illuminating state comprising: a non-contact motion sensor arranged to sense a movement of a hand near the lighting apparatus; and a controller arranged to control the lighting apparatus in the non-illuminating state to change from the non-illuminating state to the illuminating state in response to the movement of hand sensed by the non-contact motion sensor, and to control the lighting apparatus in the illuminating state to cause a change in illumination with the illuminating state kept in response to the same movement of hand sensed by the non-contact motion sensor.

The invention claimed is: 
     
       1. A lighting apparatus for use with a plurality of light emitting diodes comprising:
 a power source arranged to supply the plurality of light emitting diodes with electric power for illumination; 
 a first controller arranged to change the number of the light emitting diodes which are supplied with electric power for illumination by the power source, and to determine a maximum limit of electric power to be supplied to each of the light emitting diodes in dependence on the number of the light emitting diodes which are supplied with electric power for illumination; and 
 a second controller arranged to change the electric power to be actually supplied to each of the light emitting diodes the number of which is changed by the first controller, the second controller controlling the electric power independently from the first controller but within the maximum limit determined by the first controller to optionally change a luminance attained by the light emitting diodes to any desired luminance within the maximum limit; and 
 a heat radiator having a heat radiating capacity, the heat radiator being arranged for use in common by the plurality of light emitting diodes, wherein the first controller is arranged to determine the maximum limit of power to be supplied to each of the light emitting diodes so that a total heat generated by the light emitting diodes which are supplied with electric power for illumination by the control of the second controller does not exceed the heat radiating capacity of the heat radiator, and 
 wherein the first controller is arranged to decrease the maximum limit of power to be supplied to each of the light emitting diodes if the number of the light emitting diodes which are supplied with electric power for illumination is increased and to increase the maximum limit of power to be supplied to each of the light emitting diodes if the number of the light emitting diodes which are supplied with electric power for illumination is decreased. 
 
     
     
       2. The lighting apparatus according to  claim 1 , wherein the first controller is arranged to determine the maximum limit of power to be supplied to each of the light emitting diodes in accordance with heat radiating capacity of the heat radiator to be shared by the light emitting diodes which are supplied with electric power for illumination, the capacity per each of the light emitting diodes changing in dependence on the change in the number of the light emitting diodes which are supplied with electric power for illumination. 
     
     
       3. The lighting apparatus according to  claim 1 , wherein the first controller is arranged to change a size of an illuminating area to be illuminated by the lighting apparatus by means of the change in the number of light emitting diodes which are supplied with electric power for illumination by the power source. 
     
     
       4. The lighting apparatus according to  claim 1 , wherein the first controller is arranged to shift an illuminating area to be illuminated by the lighting apparatus by means of the change in the number of light emitting diodes which are supplied with electric power for illumination by the power source. 
     
     
       5. A lighting apparatus according to  claim 1  further comprising:
 a third controller arranged to automatically change a color temperature attained by the light emitting diodes to a different color temperature in dependence on the change in the luminance controlled by the first controller. 
 
     
     
       6. The lighting apparatus according to  claim 5 , wherein the third controller is arranged to lower color temperature attained by the light emitting diodes with the luminance lowered by the first controller. 
     
     
       7. The lighting apparatus according to  claim 5  further comprising a memory arranged to store a predetermined color temperature for the control of the third controller. 
     
     
       8. The lighting apparatus according to  claim 7 , wherein the memory is arranged to store a predetermined relationship between a predetermined luminance and a predetermined color temperature to control the second and third controllers. 
     
     
       9. The lighting apparatus according to  claim 8 , wherein the memory stores a first relationship between a higher luminance and a higher color temperature and further stores a second relationship between a lower luminance and a lower color temperature. 
     
     
       10. The lighting apparatus according to  claim 5 , wherein the plurality of diodes including diodes of different color temperatures, and wherein the third controller is arranged to change color temperature attained by the light emitting diodes by means of controlling the diodes of different color temperatures in different manners, respectively. 
     
     
       11. The lighting apparatus according to  claim 1 , wherein the second controller is arranged to vary the power to be actually supplied to each of the light emitting diodes between a minimum limit to the maximum limit, wherein the maximum limit is changed in dependence on the number of the light emitting diodes which are supplied with electric power for illumination, wherein the first controller is arranged to increase the variation range of the power between the lower limit and the maximum limit by the second controller when the first controller decreases the number of the light emitting diodes which are supplied with electric power for illumination. 
     
     
       12. The lighting apparatus according to  claim 1 , wherein the first controller is arranged to broaden the illuminating area to be illuminated by the lighting apparatus by increasing the number of the light emitting diodes supplied with electric power for illumination by the power source and to limit the illuminating area by decreasing the number of the light emitting diodes which are supplied with electric power for illumination by the power source. 
     
     
       13. The lighting apparatus according to  claim 1 , wherein the first controller is arranged to shift an illuminating area to be illuminated by the lighting apparatus by substitution of the light emitting diodes that are supplied with electric power for illumination by the power source, wherein the substitution includes replacement of a group of the light emitting diodes covering an illuminating area by another group of the light emitting diodes covering another illuminating area.